math

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Two trucks left buck's trucks traveling in opposite directions. One truck traveled at a rate of 70km/h, the other at 80km/h. After how many hours were the trucks 900km apart?

I got 3 hours as my answer, but I don't think that's right...

  • math -

    Never minds. I see my mistake. It's really 6 hours.

  • math -

    You could easily check your answer.
    first truck went 3(70) or 210 km
    2nd truck went 3(80) = 240 km

    nope, that does not add up to 900, so


    let the time be t hours
    70t + 80t = 900
    150t = 900
    t = 6

    I will leave it up to you to check my answer.

  • math -

    thanks. I though because you added 70t and 80t there would be 2ts. But no.

  • math -

    njjjbb

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